Clearwire shares were trading below Sprint's offer price, an indication investors may not yet agree to a sale.

Overland Park, Kan.-based Sprint increased its offer for the nearly 50% of Clearwire that it doesn't already own by nearly 15%, from $2.97. The deal would pay minority shareholders about $2.5 billion and value the entire company at $10.7 billion, including debt.

Sprint CEO Dan Hesse is making a play to wrap up the Clearwire stake, as he tries to close a sale of his own company to Japanese telecom Softbank Corp. Clearwire postponed a shareholder vote on the sale from Tuesday to May 31. Sprint needs approval from a majority of Clearwire's minority shareholders. Comcast Corp., Intel Corp. and Bright House Networks LLC, which together hold 26%, have agreed to vote in favor of the deal.

The question is whether the swing votes will accept what Sprint called its "best and final offer."

Kevin Smithen of Macquarie Group Ltd. suggested in a report that the improved bid will still come up short.

"We believe the $3.40 offer is still not enough and think it will take a minimum of $3.75 to sway enough arbs/hedge funds to support the deal," Smithen wrote. Wells Fargo Securities LLC analyst Jennifer Fritzsche wrote that the offer would likely win approval, with some stakeholders maintaining their objections.

The largest of the independent, Crest Financial Ltd., objected to the new price. Crest holds more than 8% of the Class A shares. The Houston firm interpreted Tuesday's announcement by Sprint as an admission that the carrier did not have adequate support.

"Sprint's decision to increase its offer price and request an adjournment reveals that Sprint was unable to secure a majority of the non-Sprint, 'minority' stockholder votes -- even though Sprint attempted to pack that 'minority' with stockholders that are commercially tied to Sprint and Clearwire have already agreed to vote in favor of the merger and sell their shares to Sprint even if the merger is rejected," Crest General Counsel David Schumacher said in a statement.

With Sprint holding a majority of Clearwire's stock, the other investors are essentially captive.

During a conference call with analysts, satellite TV tycoon expounds upon possibility of a merger with T-Mobile or DirectTV, his pursuit of Sprint and Clearwire, and allegations of fraud in LightSquared bankruptcy.